It is fairly common for people to carry personal belongings and other goods around in backpacks, satchels, handbags, or other portable containers. Typically, the portable containers have some sort of bag, box, or wrap form, and can be closed so that the contents are more or less entirely concealed within the interior of the portable container. Often, the portable container may be so secured with a zipper or similar fastener. A drawback of this system is that when users forget to fasten their portable container closed, objects may fall out or be more easily stolen. As it is easy to forget to secure one's backpack or handbag, this is a common problem.
In view of the above, there is a need for a way to alert users that they have left portable containers opened as they carry them.